1. Technical Field
The present invention relates to a closure for unthreaded pipes and other unthreaded cylindrical members. More particularly, the present invention is a multi-level cap which is substantially comprised of elastomeric material and which can accommodate several different commercially available, standard sized pipes, one pipe at a time.
2. Background
Generally, the ends of threaded pipes can be closed by removable screw-on caps, and the ends of unthreaded pipes can be closed by removable plastic caps. For example, plastic caps can be used to close the ends of pipes or conduits which are to be buried underground long-term, such as the pipes or conduits used to protect telephone or electrical lines, or short-term, such as the overnight burial of a pipe in a trench as a safety or sanitary measure until work can begin the following work day.
Plastic caps can be used on the ends of unthreaded pipes as test caps. For example, when a residential or commercial building is under construction, a plumber (or other worker) will ordinarily lay in a system of pipes, cap off the ends of the pipes, then fill the system with water to test it for leaks. If there are no leaks, the pipes can be uncapped and the pipe lengths can be extended or the system can be otherwise completed. Test caps can be used on pipes in water or sewage treatment systems. Unfortunately, the plumber must carry a number of caps of all different standard-sizes (such as 2 inch, 4 inch and 6 inch caps) for the various standard pipe sizes he or she may encounter while testing a plumbing system. Currently, one cap fits only one size of pipe opening. These existing caps are called here "single" caps, versus the "multi-level" caps of the present invention. On a plumbing system for a residence, for example, a plumber could use about 12 to 15 single caps of several different sizes. On a larger project, such as a commercial building, hundreds of caps could be used for testing a system. Although these single caps are relatively inexpensive, it is troublesome to maintain an inventory of many different-sized single caps, and it can be a waste of expensive labor for work to halt while the correctly sized single cap is obtained.
The multi-level cap of the present invention resolves these problems. The multi-level cap is for use on one pipe opening at a time, but it will fit over any of several different sizes of pipe openings, depending upon the number and sizes of the levels in the cap. The plumber or other worker can grab one multi-level cap rather than having to hunt for the right sized single cap. For example, a tri-level cap of the present invention fits three different sized pipes and is therefore much more likely to fit the pipe in question. With the multi-level cap, the plumber can prevent inconvenient and aggravating work stoppages for trips to his or her truck or to the plumbing supply store to procure the right-size single cap. If the plumber has multi-level caps of the present invention available, he or she need not waste time stocking and handling many single caps of various sizes. The multi-level cap of the present invention also works well with a release valve in the top to release pressure which can build up in the plumbing system.